I've kept dwarf puffers in this tank prior to the otos joining them, and I'm pretty sure they took out all the non-MTS snails I may have had in there in over a year in there. I've not 'transplanted' any plants TO this tank (but have moved trimmings FROM it to other tanks), so no hitchhiking eggs or snails.
Once I took the puffers out (they live in a diff tank now), I then added a few MTS.
I'm not convinced they are oto eggs anymore, as they have not hatched. Perhaps non-viable eggs...dunno. The last time, they hatched on day 3. This may be another species, so I'll leave em until they hatch or dissappear. But I don't think I have oto fry in my future